Room-temperature relaxor ferroelectricity and photovoltaic effects in tin titanate directly deposited on silicon substrate
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Tin titanate (SnTiO3) has been notoriously impossible to prepare as a thin-film ferroelectric, probably because high-temperature annealing converts much of the Sn2+ to Sn4+. In the present paper, we show two things: first, perovskite phase SnTiO3 can be prepared by ALD directly onto p-type Si substrates; and second, these films exhibit ferroelectric switching at room temperature, with p-type Si acting as electrodes. X-ray diffraction (XRD) measurements reveal that the film is single-phase, preferred-orientation ferroelectric perovskite SnTiO3. Our films showed well-saturated, square and repeatable hysteresis loopsof around 3 μC/cm2 remnant polarization at room temperature, as detected by out-of-plane polarization versus electric field (P-E) and field cycling measurements. Furthermore, photovoltaic and photoferroelectricity were found in Pt/SnTiO3/Si/SnTiO3/Pt heterostructures, of which properties can be tuned through band gap engineering by strain according to the first-principles calculations. This is a new lead-free room-temperature ferroelectric oxide of potential device application.
Agarwal , R , Sharma , Y , Chang , S , Pitike , K , Sohn , C , Nakhmanson , S , Takoudis , C , Lee , H , Tonelli , R , Gardner , J , Scott , J F , Katiyar , R & Hong , S 2018 , ' Room-temperature relaxor ferroelectricity and photovoltaic effects in tin titanate directly deposited on silicon substrate ' Physical Review. B, Condensed matter and materials physics , vol 97 , no. 5 , 054109 . DOI: 10.1103/PhysRevB.97.054109
Physical Review. B, Condensed matter and materials physics
© 2018 American Physical Society. This work has been made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1103/PhysRevB.97.054109
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